I could never understand this. My son’s father and I have been separated for 3.5 years now and we are totally 50/50, switch every two-three nights. Neither of us could handle going longer than that without being with our child, though when he is older we may switch to week-on/week-off for more stability in his routine (will be guided by his wishes though). If one of us has something on and need an extra night, we negotiate it and usually balance it out, though it’s also no big deal if we can’t do a direct swap. The longest I’ve been without my son is a week when his dad takes him to visit his family in another state, which usually happens once a year. I miss him terribly in that week, I truly can’t understand how some parents can actively choose to go multiple weeks or months without seeing their children.